1. Field of the Invention
The invention relates to automobiles and more particularly to a system and method of selecting optimum gear of automobile.
2. Description of Related Art
Energy saving and living a low carbon life are trends as petroleum price increases significantly. Emission of automobiles is the major pollution source of cities worldwide. Taking public transportation is encouraged by governments. Further, how to lower fuel consumption of an automobile is an issue of interest. High performance engines and strict emission laws also play a role in increasing fuel efficiency. Furthermore, good driving habits contribute to the lowering of fuel consumption. Many drivers can lower fuel consumption by 25% after a short period of training based on a study released by Ford Motor Company. Further, many drivers, after being trained to one to one and half year, can lower fuel consumption by 15% in comparison with drivers not being trained. This means the longer of training time the fuel consumption of an automobile driven by a driver being trained is lower. Thus, it is desirable of developing a technique of training a driver at any time and alerting a driver of good driving habits.
China Patent Application No. 201010157270.5 discloses an apparatus of selecting optimum gear and alerting same to a driver of an automobile powered by a diesel engine. It is characterized in that the optimum gear is selected based on data points of a curve representing constant speed for maximum operating efficiency, and the selected optimum gear is shown on a display for alerting a driver. It is further characterized in that CRUISE software is used to calculate torques at different gear ratios, full load, and no load of an automobile prior to implementation. Furthermore, different loads and fuel consumption curves of different gear ratios for determining optimum vehicle speed are calculated by either experiments or simulations. The patent has the following drawbacks:
Accuracy of the selection of optimum gear depends on the simulation result which however, has variances. Thus, the selection of optimum gear is not reliable.
Great processing time and large memory are required due to the storage of a great number of fuel consumption curves of different gear ratios. Thus, the apparatus is bulky and the cost is prohibitively high.
Fuel consumption curves of different gear ratios are required to calculate if the automobile has been modified or has a lower performance due to wear. Thus, its application is limited.
Thus, the need for improvement still exists.